Study on the distillation rates of LiCl–KCl eutectic salt under different vacuum conditions

A study on the distillation rate of LiCl–KCl eutectic salt under different vacuums from 0.5 to 50 Torr was performed by using thermogravimetric (TG) method. A distillation rate of the order of 10−4–10−5 mol cm−2 s−1 was obtainable at temperatures of 1200–1300 K and vacuums of 5–50 Torr. Based on the non-isothermal TG data, model distillation flux equations could be derived as a function of temperature. Pure gas-phase and gas–liquid interfacial resistances at different vacuum conditions were evaluated from the comparison of experimental vaporization fluxes with the maximum flux obtained from the kinetic theory of gas. The difference between interfacial mass transfer coefficients and gas-phase ones increases with the temperature. Gas-phase resistance is much greater than that of the phase transition between condensed and gas phases at tested vacuum conditions of 0.5–50 Torr.